This is a battery holder to mount to the bottom of the power pod used on a variety of Flite Test models. I'm using this one on a bloody baron.
You can attach it to the bottom of the power pod with double sided foam mounting tape or hot glue.
The strap I used can be found here
https://www.amazon.com/gp/product/B079SV4X74?ie=UTF8&tag=3dprinting04b-20&camp=1789&linkCode=xm2&creativeASIN=B079T2B9WP&th=1
The author marked this model as their own original creation. Imported from Thingiverse.